title: Atrophic cardiomyocyte signaling in hypertensive heart disease.
abstract: Cardinal pathological features of hypertensive heart disease (HHD) include not only hypertrophied cardiomyocytes and foci of scattered microscopic scarring, a footprint of prior necrosis, but also small myocytes ensnared by fibrillar collagen where disuse atrophy with protein degradation would be predicted. Whether atrophic signaling is concordant with the appearance of HHD and involves oxidative and endoplasmic reticulum (ER) stress remains unexplored. Herein, we examine these possibilities focusing on the left ventricle and cardiomyocytes harvested from hypertensive rats receiving 4 weeks aldosterone/salt treatment (ALDOST) alone or together with ZnSO₄, a nonvasoactive antioxidant, with the potential to attenuate atrophy and optimize hypertrophy. Compared with untreated age-/sex-/strain-matched controls, ALDOST was accompanied by (1) left ventricle hypertrophy with preserved systolic function; (2) concordant cardiomyocyte atrophy (<1000 μm²) found at sites bordering on fibrosis where they were reexpressing β-myosin heavy chain; and (3) upregulation of ubiquitin ligases, muscle RING-finger protein-1 and atrogin-1, and elevated 8-isoprostane and unfolded protein ER response with messenger RNA upregulation of stress markers. ZnSO₄ cotreatment reduced lipid peroxidation, fibrosis, and the number of atrophic myocytes, together with a further increase in cell area and width of atrophied and hypertrophied myocytes, and improved systolic function but did not attenuate elevated blood pressure. We conclude that atrophic signaling, concordant with hypertrophy, occurs in the presence of a reparative fibrosis and induction of oxidative and ER stress at sites of scarring where myocytes are atrophied. ZnSO₄ cotreatment in HHD with ALDOST attenuates the number of atrophic myocytes, optimizes size of atrophied and hypertrophied myocytes, and improves systolic function.
authors.affiliation: *Department of Medicine, Division of Cardiovascular Diseases; Departments of †Obstetrics and Gynecology; and ‡Microbiology, Immunology and Biochemistry; and §Department of Medicine, Division of Endocrinology, University of Tennessee Health Science Center, Memphis, TN. G. Kamalov is now with the Division of Cardiovascular Medicine, Ohio State University, Columbus, OH.
authors.forename: German
authors.initials: G
authors.lastname: Kamalov
authors.forename: Wenyuan
authors.initials: W
authors.lastname: Zhao
authors.forename: Tieqiang
authors.initials: T
authors.lastname: Zhao
authors.forename: Yao
authors.initials: Y
authors.lastname: Sun
authors.forename: Robert A
authors.initials: RA
authors.lastname: Ahokas
authors.forename: Tony N
authors.initials: TN
authors.lastname: Marion
authors.forename: Fahed
authors.initials: F
authors.lastname: Al Darazi
authors.forename: Ivan C
authors.initials: IC
authors.lastname: Gerling
authors.forename: Syamal K
authors.initials: SK
authors.lastname: Bhattacharya
authors.forename: Karl T
authors.initials: KT
authors.lastname: Weber
mesh_terms: D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology / Q000627:therapeutic use; D000975:Antioxidants / Q000494:pharmacology / Q000627:therapeutic use; D002316:Cardiotonic Agents / Q000494:pharmacology / Q000627:therapeutic use; D048429:Cell Size / Q000187:drug effects; D002478:Cells, Cultured; D004195:Disease Models, Animal; D059865:Endoplasmic Reticulum Stress / Q000187:drug effects; D006352:Heart Ventricles / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D006973:Hypertension / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D017379:Hypertrophy, Left Ventricular / Q000209:etiology* / Q000517:prevention & control; D008297:Male; D009124:Muscle Proteins / Q000819:agonists / Q000235:genetics / Q000378:metabolism*; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D018384:Oxidative Stress / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D044843:SKP Cullin F-Box Protein Ligases / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D000070584:Tripartite Motif Proteins; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D000959:Antihypertensive Agents; D000975:Antioxidants; D002316:Cardiotonic Agents; D009124:Muscle Proteins; D000070584:Tripartite Motif Proteins; C486692:Fbxo32 protein, rat; D044843:SKP Cullin F-Box Protein Ligases; C499086:Trim63 protein, rat; D044767:Ubiquitin-Protein Ligases